'I think it is perfectly reasonable to not want a name that is spelt and said vastly differently. '
LOL, so you take S-O-R-C-H-A and pronounce it Sorsha, when the obvious spelling of Sorsha would be S-O-R-S-H-A?
I seem to recall one of the reasons Sorcha Cusack was known as Scorcher Cusack was that that CH in the middle lent itself to a CH pronunciation.
You have chosen a name (Orla) with a spelling that is perfectly acceptable in modern Irish. The fact that it is completely correctly spelled and pronounced (though possibly the R is more of a W sound for you) seems to have happened completely accidentally however. You were right for the wrong reasons.
Caitlin/Conor etc are completely new names based on Irish names that are pronounced Kawtchleen and Cruhoor in Connemara Irish. The surname O'Connor is, in Irish, Ó Conchubhair, pronounced 'O Cruhoor' in Connemara Irish. Similarly, Sorsha, where the first and second syllables are both pronounced differently from the original name Sur-i-kha, is a new name and deserves a new spelling. Caitlin/Katelyn, and Connor/Conor are new English names with perfectly adequate spellings that convey their pronunciation, and therefore not wrong.
Conor is not pronounced 'Cruhoor' in Irish. Conchubhair is.
Caitlin is not pronounced 'Kate-lin' in Irish, whereas CáitlÃn is.
Sorsha is not pronounced 'Sorsha' in Irish but Sorcha is. Because it is an Irish name, whereas Sorsha is not.
If you want to be logical, then you should choose the Sorsha spelling. However, logic is not your thing either apparently.
And Cuchulainn is not 'pretty much phonetic too' either -- how do you pronounce it?
I agree with Superfly wrt giving Brits a bit more credit where pronunciation of names is concerned. Look at Niamh, Fionnuala, RuairÃ. etc.